THE 25TH ANNUAL PUTNAM COUNTY SPELLING BEE: Emy Baysic is all perky defiance as the over-programmed Asian prodigy.

“Have you ever been in a gymnasium in the round before?” asks one of the nerdy participants toward the top of The 25th Annual Putnam County Spelling Bee at North Shore Music Theatre (through August 31). And yes, it is strange to witness this delightfully quirky musical set in a middle-school gym in NSMT’s large arena. But the ad lib reflects what’s best about William Finn & Rachel Sheinkin’s unlikely Broadway hit: the oft-ironic witticisms and asides that trump Finn’s catchy but unmemorable score and the feel-good-about-yourself message that’s built into the small-scale songfest in which six young adults play nervous, oddball adolescents vying for top orthographic honors — plus a chance at national glory — at a county spelling bee.

The 25th Annual Putnam County Spelling Bee began life as an original improvisational play called C-R-E-P-U-S-C-U-L-E (take that to Broadway) created by Rebecca Feldman and a group called the Farm. The musical version — which retains an improvisational edge in that it includes several audience members as spellers — began life in 2004 at the Pittsfield–based Barrington Stage Company, which claimed the right to the first regional production following the show’s odyssey to Broadway. The NSMT staging, directed by Jeremy Dobrish, is a co-production with Barrington Stage that has been reworked for the round. And though the hyperactive adolescent excitement seems smaller than it did when the show played at Boston’s Wilbur Theatre, the show’s geeky, idiosyncratic charm for the most part survives the transition from proscenium to doughnut.

The spelling bee has become a pervasive metaphor of late, from the Myla Goldberg novel Bee Season (which became a 2005 film) to the 2006 movie Akeelah and the Bee to the documentary Spelling Bee. But none of those features the outlandish likes of stocky, sloppy William Barfee, who suffers from a “mucus-membrane disorder” as well as from a nut allergy so acute he can’t be in the presence of still-packaged peanut M&Ms and who spells with the aid of a “magic foot” snaking in script across the floor. Neither do they offer hippy-dippy, home-schooled Leaf Coneybear or pint-sized gay activist Logainne Schwarzandgrubenierre, whose impossible last name joins those of her two pressuring dads. Really, as these linguistic warriors deploy their painful backstories and hifalutin phonemes, you don’t know whether to laugh or cry.

Many of Finn’s songs limn the inner lives of the insecure bee contestants, so most of the hilarity emanates from Sheinkin’s Tony-winning book, which makes hay of defining and using in sentences the words thrown at the spellers, from “phylactery” to “weltanschauung.” But Finn gets his comic licks in, notably in the humiliation-fueled “My Unfortunate Erection,” in which Boy Scout–uniformed former champ Chip Tolentino — the terrific Miguel Cervantes of SpeakEasy Stage Company Bat Boy fame — decries the boner that distracted him from correctly spelling “tittup.” Having been forcibly removed from the competition, Chip returns as a snack vendor for his bravura turn, which he performs while angrily slinging treats into the audience, a healthy contingent of which proves it knows how to spell c-a-t-c-h.

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